A data processing device typically employs a cache for storage and retrieval of recently accessed information. However, information stored in the cache can be stored or retrieved in an erroneous state due to hard errors, resulting from a defective storage cell, or soft errors, such as errors resulting from alpha particle disruption or marginal operation of a storage cell. To protect against such errors, the data processing device can employ an error protection module that detects, and in some cases corrects, errors in information retrieved from the cache. In addition, the data processing device can employ a lockout scheme, whereby cache lines for which errors have been detected are rendered inaccessible.